Pre-wetting device for printing press



Aug. 18, 1964 P. H. HILPMAN ETAL I 3,144,823

PEE-WETTING DEVICE Foa PRINTING PRESS Filed Aug. 1e, 1962 Y 2 sheets-sheet 1 INVENTORS PAUL HILPMAN BY LEROY EALBERT 7T fvfy Aug. 18, 1964 P. H. HILPMAN ETAL 3,144,823

PRE-WEITING DEVICE FOR PRINTING PREzss 2 Sheets-Sheet 2 Filed Aug. 16, 1962 v L l r INVENTORS PAUL H/LPMAN LEROY/: ALBERT United States Patent O PRE-WETTING DEVICE FOR PRINTING PRESS Paul H. Hilpman, Garden City, and Leroy Fred Albert,

Brooklyn, N.Y., assignors, by mesne assignments, to

Fairchild Camera and Instrument Corporatioma corporation of Delaware Filed Aug. 16, 1962, Ser. No. 217,321 3 Claims. (Cl. 101-147) The present invention relates to printing machines and the like and more particularly to short run offset printing presses of the type disclosed in Letters Patent 2,759,416 wherein a paper plate or master is automatically attached to a rotating printing cylinder. More particularly, it relates to means for preparing such paper plates for a printing operation.

In order to insure that a clean image is printed, it has been customary for the press operator to pre-wet the paper plate prior to dampening and inking the plate with the conventional dampening and inking rollers. This was accomplished by moistening a cloth with dampening solution and .applying the solution directly to the plate. The operation was generally performed at a work table provided in a convenient location adjacent the printing press, although it could be done after the plate was attached to the printing cylinder.

While the foregoing pre-wetting arrangement has been widely used, it has not been favored in oiiice establishments that use short run printing presses. The requirement is that the work area' be as neat as possible and take a minimum of space, and that the procedure to be followed by the operator be simple and direct without adversely affecting the printing results.

The primary object of the present invention is to provide an improved means for pre-wetting a paper printing plate after it has been attached to the printing cylinder.

Printing machines of the type disclosed in the aforementioned patent have a plate cylinder which comprises a plate segment and a platen or impression segment and an offset blanket cylinder which cooperates therewith to provide -a printing couple. The arrangement is such that the paper plate is secured to the plate segment of the printing cylinder where it is dampened and inked, the thus formed ink image is transferred to the offset blanket on the blanket cylinder and then to a sheet of paper secured to the impression segment during the printing cycle.

In carrying out the invention a pre-wetting device is provided that is pivotally mounted on the machine frame and resiliently biased out of engagement with the plate cylinder. The device comprises a flat plate having a slot therein extending across the width of the machine. A dampening roller is rotatably mounted to project through said slot. By manually depressing the device the dampening roller is brought into engagement with a printing plate mounted on the plate cylinder. However, since the plate cylinder includes an impression segment that is never dampened, means are also provided to positively disengage the prewetting element from the impression segment even when an operator may be manually depressing the device. Of course, if the press were of the three cylinder type wherein the plate cylinder does not include an impression segment, the means just referred to are not provided.

Features yand -advantages of the present invention may be gained from the foregoing and from the description of a preferred embodiment thereof which follows.

In the drawings:

FIG. l is a partial side elevational view of a printing machine embodying the pre-wetting device of the present invention;

FIG. 2 is a front elevational view of the pre-wetting device;

FIG. 3 is a bottom plan view thereof; and

FIG. 4 is a sectional view in elevation, taken on line 4-4 0f FIG. 2 showing the pre-wetting device in its depressed position.

In the drawings, which illustrate a portion of an offset printing press, two separate side members 10 secured to each other by suitable cross framing (not shown) form an integral base wherein :all controls and mechanism of the press are mounted.

Situated between and journaled to both of the side members is shaft 11 which supponts a rotating plate cylinder 12 consisting of a plate segment 13 and a platen of impression segment 14. The segments are fastened to the outside periphery of end plates 15 which in turn are secured to the above mentioned shaft 11. Each segment, 13 and 14, carries its own gripper mechanism, 17 and 18 respectively, in slots provided at the leading edge thereof. The gripper mechanism 17 holds a paper plate 19 in correct registry on the plate segments while mechanism 18 performs a similar function for the sheets to be printed on the impression segment. Also mounted on each side of the plate cylinder 12 adjacent to the platen on impression segment 14 is a crescent shaped cam 20, the purpose of which will be hereinafter described.

A blanket cylinder 22, whose function is to receive the inked image from the plate and transpose it to the paper that is to be printed, is mounted on shaft 21 above the printing cylinder 12.

Positioned above the printing cylinder 12 and forward of the blanket cylinder 22 is the pre-wetting device 30. The device is pivotally supported on the press by means of pins 31 which extend into holes in flanges 32 formed at the upper ends of supporting brackets 33. The brackets in turn are screwed to the side frames 1t) of the press. Unit 3i) can be rotated counter-clockwise away from the printing cylinder, to provide accessibility thereto should such be necessary, but movement toward the cylinder is restricted by means presently to be described.

The pre-wetting unit 30 itself comprises a main supporting plate 34 having within its outer edges and transversing nearly its en-tire length a cutout portion 35. End members 37 are fastened to the underside of the support plate 34 near both ends of the cutout pontion 35 by screws 36. The upper halves of the end members extend above the main plate 34 act .as supporting surface-s for a cover plate 38. The plate is held in place by thumbscrews 39 and forms =a rectangular shaped housing for the prewetting roller `4t). Screwed to the outside of the lower portion of end members 37 by roller retaining screws 41 are cam follower rollers 42 which engage the above mentioned crescent shaped cams 20.

Each end of pre-wetting roller 40 is provided with a cup-like depression into which is placed a bushing member 48. A stub shaft 49 that supports the roller for rotary movement is provided with a hexagonal head 45 which rides in a groove 44 cut into the inside surface of end member 37. A pin 46 loosely fitted through a hole in cover plate 38 is provided with a washer-like member 57 that abuts the head 45 of stub shaft 49'. A compression spring 47 is provided around pin 46 between member 57 and the underside of cover plate 38. The arrangement is such that head 45 is biased into engagement with the bottom of groove 44 and when handle 56 is depressed in la pre-wetting operation, roller 40 is resiliently urged into engagement with the printing plate being dampened.

The pre-wetting roller itself consists of an inner core 50, which may be of felt, acting as a reservoir for the dampening solution while the outer cloth covering 51 insures an even distribution of the solution over the plate Patented Aug. 18, 1964 19. If it is desired to remove the roller from the device 30 in order, for example, to replace covering 51, this can be accomplished simply by removing thumb nuts 39 and cover plate 38. The roller can then be lifted from end members 37.

It was noted hereinbefore that pre-wetting device 30 is pivotally supported in the side frame of the printing press. However, roller 40 is normally biased out of engagement with printing plate 19 by the action of compression spring 53 which is located between the nut 58 threaded on bolt 54 and the underside of plate 34. The nut normally rests on bracket 33 and spring 53 biases plate 34 against the head of bolt 54 to lift roller 40 clear of the rotating printing cylinder.

During normal operation of the press, a printing plate is attached to the printing cylinder either manually or automatically. The operator, preparatory to a pre-wetting operation, saturates the roller 40 by pouring or squirting dampening solution through the longitudinal opening between the top of cover plate 38 and plate 34 directly onto the roller 4i). The operator thereupon depresses handle 56 to lower roller 4i) into contact with printing plate 19. It is to be noted that regardless of the force exerted by the operator on handle 56, roller 40 contacts plate 19 under the controlled force of spring 47. In the embodiment shown where the printing cylinder comprises a plate segment which carries a plate to be dampened and an impression segment that is not dampened, it is not necessary for the operator :to depress and release handle 56 once for each rotation of the printing cylinder.. Rather, the crescent shaped cams 20 cooperating with follower rollers 42 automatically raise the pre-wetting device each time that the impression segment of the cylinder 12 comes under pre-wetting roller 40.

Inasmuch as many apparently widely different embodiments of 4the invention can be made without departing from the spirit or scope thereof, it is to be understood 4 that the specification and drawing are to be interpreted as illustrative rather than in a limiting sense.

What is claimed is: i

1. A pre-wetting device for a printing press having a pair of spaced-apart side frames and a printing cylinder rotatably supported therebetween, said device comprising a pre-wetting roller, a suppor-t for said roller, said support being pivotally mounted on the side frames of the press adjacent the printing cylinder, means for resiliently mounting said roller on said support, and means for resiliently urging said roller support away from said printing cylinder.

2. A pre-wetting device according to claim 1 wherein said printing cylinder comprises a plate segment and an impression segment, including a cam mounted on the printing cylinder adjacent the impression segment and a cam follower rotatably supported on said roller mounting means.

3. A pre-wetting device for a printing press having a pair of spaced-apart side frames and a printing cylinder rotatably supported therebetween, said device comprising a support plate pivotally mounted on the side frames of the press adjacent the printing cylinder, means for resiliently urging said plate away from the printing cylinder, a pre-wetting roller rotatably mounted on said support plate, and means operative when said support plate is pivoted towards the printing cylinder for a pre-wetting operation for resiliently biasing said pre-wetting roller into engagement with the printing cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A PRE-WETTING DEVICE FOR A PRINTING PRESS HAVING A PAIR OF SPACED-APART SIDE FRAMES AND A PRINTING CYLINDER ROTATABLY SUPPORTED THEREBETWEEN, SAID DEVICE COMPRISING A PRE-WETTING ROLLER, A SUPPORT FOR SAID ROLLER, SAID SUPPORT BEING PIVOTALLY MOUNTED ON THE SIDE FRAMES OF THE PRESS ADJACENT THE PRINTING CYLINDER, MEANS FOR RESILIENTLY 